Organic polymeric compositions such as polyolefins, which are commonly utilized as dielectric insulating materials for electrical wires and other conductors, comprise materials which are typically highly susceptible to a loss of physical form and/or structural integrity when subjected to flame or combustion temperatures. The loss of physical form and/or structural integrity in these polymeric compositions at the temperatures of flame or burning conditions is normally accompanied by the flow and dripping of their combustible components which can be an especially hazardous source of material for the spreading flame.
As used in the claims and through this specification, the terms "flame temperatures" or "combustion temperatures" are to be understood to mean the temperature conditions at which oxidation takes place so rapidly that the products thereof are rendered incandescent. The terms "silphenylene" and "silarylenesiloxane-polydiorganosiloxane copolymers" are herein used interchangeably.
Flame propagation due to flowing and dripping of combustible organic electrical insulating materials is particularly critical in locations within and about motors and machinery because of the general presence or close proximity of oils and other highly combustible lubricants and other materials which can, in turn, further propagate and expand the fire hazard and its spread. Furthermore, where electrical or electronic components are present, circuit integrity can be impaired by the dripping or flowing of combustible organic insulation materials and by the consequential spread of flame and fire.
Previously, most of the methods of imparting flame-retardancy to polymeric compositions involved adding highly halogenated compounds to the polymer. This practice not only produced a polymer which was very corrosive to some materials it may have come into contact with but also produced a polymer which could give off toxic gases when exposed to flame or combustion temperatures.